What is ROM Types of ROM Explained

What is ROM and its types

Do you want to know what is ROM – (What is ROM) then in this post you have been given the types of ROM and complete information about ROM in easy and simple words. Let us tell you what is Rome after all.

What is ROM

The full form of ROM is Read Only Memory. It is a memory device or storage medium that stores information and data permanently. Along with RAM, it is also the primary memory unit of the computer. It is called Read Only Memory because we can only read but not write the program and data stored in it.

The manufacturer of ROM fills programs in ROM at the time of creation of ROM. After this, the contents of the ROM cannot be changed which means that you cannot later reprogram, rewrite or delete its contents. However, there are some types of ROM where you can modify the data.

ROM contains special internal electronic fuses that can be programmed for a unique interconnection pattern. Once the pattern or information is installed, it remains inside the unit of ROM even when the power is turned off

Thus ROM is a non-volatile memory i.e. even if the power is turned off or you also turn off the computer. Even then the data stored inside the ROM is not deleted and remains safe in the ROM.

Information is added to RAM in the form of bits by a process known as ROM programming.

ROM is used in the cartridge of video game console. Which allows the system to run multiple games. Store data permanently on other electronic devices like PC, Tablets, Smartphones, TV etc. An example of ROM is also.

For example – when you start your computer, the screen is not visible immediately. It takes time to appear because the ROM contains Startup Instruction Stores which are required to start the computer during the booting process.

The job of the booting process is to start the computer. It loads the operating system into the main memory, RAM installed on your computer. The BIOS program present in the ROM is used by the computer’s microprocessor to start the computer during the booting process. This allows you to open the computer and connect the computer to the operating system.

ROM is also used to store firmware. Firmware is a software program that is attached to the hardware or is programmed on the hardware device such as keyboard, hard drive, video card etc. This hardware is stored in the flash ROM of the device. It gives instructions to the device to communicate with other devices.

Types of ROM

• Masked ROM (MROM)
• Programmable ROM (PROM)
• Erasable and Programmable ROM (EPROM)
• Electrically Erasable and Programmable ROM (EEPROM)

Masked ROM (MROM)

This is the oldest type of Read Only Memory (ROM). It has become obsolete so it is not used anywhere in today’s world. It is a hardware memory device in which programs and instructions are stored in it while making it by the manufacturer. Therefore it is programmed at the time of manufacture and cannot be modified later.

Programmable ROM (PROM)

PROM is a blank version of ROM. It is created as blank memory and is programmed after manufacturing. We can say that it is kept empty while making. You can buy it and program it using a special tool.

To write data on the PROM chip, a device called a PROM programmer or a PROM burner is used. Programming a PROM is known as burning PROM. Once programmed, its data cannot be modified later. Therefore it is also called one-time programmable device. It is used in cell phones, video game consoles, medical devices etc.

Erasable and Programmable ROM (EPROM)

The full form of EPROM is Erasable and Programmable Read Only Memory. EPROM is a type of ROM that can be re-programmed and erased many times.

The method of erasing its data is very different. It comes with a quartz window. Through which a specific frequency of ultraviolet light is passed for about 40min to erase the data. A special tool, PROM Programmer or PROM Burner is needed to re-program it.

It is used to store programs in some micro-controllers. As in some versions of the Intel 8048 and the freescale 68HC11.

Electrically Erasable and Programmable ROM (EEPROM)

The full form of EEPROM is Electrically Erasable and Programmable Read Only Memory. EEPROM is a type of ROM memory that can be repeatedly erased and re-programmed up to 10,000 times.

It is also known as flash EEPROM. Because it is similar to Flash memory. It can be erased and electrically re-programmed without using ultraviolet light. Its access time is between 45 to 200 nanoseconds.

Data in this memory is written or erased one bit at a time. Whereas in flash memory the data is written and erased in blocks. It is used to store a small amount of data in devices such as computers and electronic systems and circuit boards. The computer’s BIOS is stored in this memory.

FLASH ROM

This is an advanced version of EEPROM. The advantage of using this memory is that you can delete or write a block of data of about 512 bytes at a particular time. Whereas, in EEPROM you can delete or write only 1 byte of data at a time. Thus this memory is faster than EEPROM.

It can be re-programmed without removing it from the computer. It has a very high access time, around 45 to 90 nanoseconds, is highly durable and can withstand high temperatures and pressures.

It is used to store or transfer data between personal computers and digital devices. It is used in USB flash drives, MP3 players, digital cameras, modems and SSDs. The BIOS of many modern computers is stored on a flash memory chip called Flash BIOS.

Advantages of ROM

The ROM is static, meaning it does not need to be refreshed frequently. Its easy to test or test. ROM is more reliable than RAM as it is non-volatile in nature i.e. the data stored inside it is permanent and that data is not deleted when power off or device is turned off. It is less expensive than RAM.

Difference between ROM and RAM

Unlike the computer’s RAM, the data in the ROM is not destroyed when the computer is powered off. ROM chip is usually used in the startup operations of the computer. Whereas the RAM chip is often used in the recurrent tasks of the computer when the operating system is configured.

Another difference between ROM and RAM is the amount of space they take up. ROM chips can only store several megabytes (MB) of data, usually between 4 and 8 MB per ROM chip.

RAM chips can store several gigabytes (GB). This storage is often between 1 and 265GB per RAM chip. 1GB is considered equal to 1024 MB. Therefore RAM exhibits a much wider memory capacity.

It is almost impossible to operate a computer using only ROM. RAM is necessary to run useful and dynamic programs. That is why both ROM and RAM chips are very necessary and play an important role in the computer.

in short

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